Fixture for on-roof installation object and fixing structure of on-roof installation object

A fixing structure of an on-roof installation object, comprising a fixture, in which the on-roof installation object is fixed to a under roofing material, the fixture further comprising:

• a substitutive roof member that includes a plate-like base part, a base opening, a tubular wall, a top face, and a pair of first guide surfaces, the base opening penetrating the base part, the tubular wall being erected from a peripheral edge of the base opening, the top face extending inwardly in a form of a plate from a top end of the tubular wall and forming a top face opening that is smaller than the base opening, the pair of first guide surfaces each extending downward from a corresponding one of peripheral sides of the top face opening so as to oppose each other, the substitutive roof member being used in place of a roof member and being made of a metal or a synthetic resin;
• and
• a mounting base that includes a pair of planar bottom plates, a pair of rising walls, a pair of extending parts, a pair of second guide surfaces, a connection part, and a fixing member mounting part, the planar bottom plates being provided in a row in such a size as to pass through the top face opening in the substitutive roof member, each rising wall being erected from an entire length of an inner-side side of a corresponding one of the pair of bottom plates, the extending parts extending sideways from a corresponding one of the rising walls to an outside edge of the bottom plates, the second guide surfaces extending along the outside edge from a corresponding one of the extending parts, the connection part connecting upper sides of the pair of rising walls, the fixing member mounting part being exposed at a top surface of the connection part for mounting a bolt or a nut,
• wherein the substitutive roof member is used in place of the roof member and is mounted on the under roofing material, and,
• with a gap provided between the mounting base and the top face opening in the substitutive roof member, the mounting base is mounted on the under roofing material, and
• wherein the on-roof installation object is fixed via the bolt or the nut that is mounted to the fixing member mounting part of the mounting base,
• wherein the pair of the second guide surfaces is guided by the pair of the first guide surfaces as the mounting base is inserted into the top face opening of the substitutive roof member.